Roller pump



Nov. 11, 1969 H. J. SADLER 3,477,377

ROLLER PUMP Filed May 22, 1967 INVESTOR. H4BEI/ c/. $401.52

I BY

- a QM m F155 40 9f 447' TOE/I/EVS United States Patent U.S. Cl. 103-136 Claims ABSTRACT OF THE DISCLOSURE A roller pump having a housing defining a pumping chamber, and a rotor rotatably mounted within the chamber with the axis of the rotor being offset from the axis of the pumping chamber, the rotor having a plurality of roller receiving slots formed about the periphery thereof and being adapted to receive rollers therein. The rollers disposed in these slots are selected so as to provide substantial clearances between the radially disposed slot faces, these slot faces being spaced apart a distance of from five percent to eleven percent greater than the diameter of the roller received therein.

A roller pump having a rotor with roller receiving slots which slots are of a width which exceeds the roller diameter by an amount of between 5 and 11 percent. This excess slot width is usable in roller pumps having a slot depth which is substantially equal to or which may exceed the roller diameter.

The utilization and construction of roller pumps is well known in the art, and generally roller pumps include a slotted rotor member arranged for eccentric rotation in a cylindrical cavity having rollers slidably received therein to permit the rollers to oscillate in a radial dimension thereby increasing and decreasing the usable fluid filling volume. This concept is well understood by those skilled in the roller pump art.

The present invention provides herein a unique design for a roller pump which includes a rotor having an excess roller slot width as compared to the normal slot width which normal width is only slightly greater than the roller diameter to permit the oscillation. It has been found that the utilization of an excess width slot provides increased fluid access to the zone below or beneath the roller while at the same time preventing any rattling, chattering or other anomalous effects in the pump during normal pumping operation. In designing this particular width slot, it has been further found that a maximum slot width must not be exceeded as if this dimension is exceeded, excessive chattering or rattling may occur between the roller and the slot surfaces. This chattering or rattling naturally would result in terrific wear elfects on both the roller and the slot, and accordingly is undesirable.

It is, therefore, an object of the present invention to provide a roller pump designed for high pressure, high volume operation having roller receiving slots extending radially outward from a rotor axis wherein the roller receiving slots are of a width exceeding the diameter of the roller.

It is a further object of the present invention to provide a roller pump having a rotor and roller construction wherein the roller receiving slots of the rotor exceed the width of the roller from between 5 to 11 percent.

These and other objects of the present invention will become apparent to those skilled in the art upon a study of the following specification, appended claims, and accompanying drawing wherein:

FIGURE 1 is an end elevation looking in the direction of the inlet and outlet of the pump;

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FIGURE 2 is a vertical section of the pump taken on the line 2-2 of FIGURE 1;

FIGURE 3 is a transverse section taken substantially along line 3-3 of FIGURE 2;

FIGURE 4 is a view similar to FIGURE 3 showing a modification of the concept; and,

FIGURE 5 is a fragmentary view particularly illustrating the inlet and outlet end of the pump taken substantially along line 55 of FIGURE 1.

In accordance with the accompanying drawing, a roller pump incorporating the concepts of the present invention includes a housing generally designated 10 and a rotor assembly generally designated 11 journaled within the housing for rotation therein. Housing 10 is conveniently formed as a two-piece housing including a first cup shape element 12 which provides a generally cylin drical inner roller contacting surface 13 and one generally arcuate end wall 14 against which the rotor 11 will bear upon rotation.

Housing section 12 further includes an axially extending boss 15 having a central passage 16 formed therein which passage is diminished inwardly towards the inner end wall 14 to provide a seat portion for a shaft journaling bearing 17, which bearing abuts with a first shoulder 18 in passage 16. A second reduced passage portion 19 provides a seat for a seal member generally designated 20, which seal member is provided to prevent loss of fluid from within housing 10.

A drive shaft opening 21 is provided inwardly of the aforementioned seal housing portion 19 such that a drive shaft 22 may extend therethrough and pass from the housing 10 to be driven on one end thereof and more preferably as illustrated in FIGURE 2 on the right side of the pump housing 10. A drainage passage 23 is provided in radially extending relation from the area defined between the seal 19 and the bearing 17 to permit any fluid which may pass through the seal to be drained from the housing 10.

The second portion of the housing 10 is generally designated 25 and includes a substantially flat, arcuate end wall 26 arranged to be received in the cylinder defined by wall 13 and engage the other side of rotor 11. This second housing member 25 is arranged in sealing relation to the first said portion 12 through the utilization of O-rings or other seal members 27 arranged in abutting relation to the end-most portions 13a of the circumferentially arranged surface 13. As illustrated in FIG URE 2, the second housing member 25 is preferably of reduced diameter at its inner end wall 26 such that the same will be received into and positively positioned with respect to the circumferential wall 13 to provide a positive rOtOr retaining cavity within the housing 10. The two housing elements may be attached and connected as by cap screws 28 or the like spaced about the periphery of the seocnd housing member 25.

Housing member 25 includes an axially extending boss member 30 arranged in opposed relation to the first of said boss members 16 which is provided with a bearing member 31 to support and rotatably engage the shaft member 22 which extends completely through the hous-' ing. In this same boss member 30, a seal 32 is provided inwardly of bearing 30, and again between the seal 32 and bearing 31, a radially extending passage 33 is pro-' 3 permit passage of fluid into the rotor area 11 of the pump.

As illutrated in FIGURES 3 and 4, the shaft 22 and of course the respective bearings 17, 31, and seals 20, 32 are arranged in eccentric relation with respect to the axis of the circumferential inner surface 13. This arrangement is necessary to obtain the proper volume increase and decrease as the rotor 11 and its associated rollers revolve within the cavity.

As illustrated in FIGURE 3, the rotor member 11 includes a plurality of radially extending slots designated respectively 45, which slots comprise, in the form shown, substantially parallel front 46a and trailing faces 46b, and a bottom portion 47. In the form shown, although the faces of the slots 45 are parallel, it should be obvious that various modifications can be included herein, and often the faces are provided "with a scoop or other relieved zone to provide fluid access to that portion of the roller receiving slots 45 which is beneath or radially inward of the roller. Such an arrangement may likewise be achieved by utilizing divergent faces rather than parallel faces.

Each of the slots 45 are proivded :with a roller member designated 48 haivng a length to extend between the end walls 14, 26, which roller member is free to radially oscillate within the slots 45 as the rotor 11 is rotatably driven within the housing 10. As illustrated in FIGURES 3 and 4, the shaft 22 and carried rotor 11 are arranged eccentrically with regard to the housing inner roller surface 13 with the rotor 11 arranged concentrically with regard to the shaft 22 such that when the shaft 22 rotates, the rotor 11 is in closer adjacent relationship to one portion of the wall 13 than it is to a diametrically opposed portion of the wall 13.

It should be noted that each of the roller members 48 are of substantially less diameter than the width between the faces 46a, 46b of the individual slots 45. It has been found that this particular variations in width is properly between 6 and 10 percent of the roller diameter and more preferably the dimensional difference has been found to be within the range of 7 to 9 perecnt of the roller 48, and 8 percent appears to be the optimum difference which will ensure a pump free of chattering or rattling.

As illutrated in FIGURES 3 and 4, a difference is contemplated as to the depth of the individual slot members 45. As illustrated in FIGURE 3, the solt depth is substantially greater than the diameter of the roller 48, while the configuration illustrated in FIGURE 4 shows the roller 48 as being of substantially the same depth as the individual slots. It has been found that this type of roller and rotor design will operate efficiently and properly whether the slot depth is determined to be greater than or approximately equal to the roller diameter.

As particularly illustrated in FIGURE 5, and as generally understood by those persons aware of roller pump operation, the inlet 40 and outlet 41 respectively are provided about a certain predetermined angular dimension with respect to the rotor 11. This particular feature of the device is not illustrated, but certainly should be understood to be of the common type construction. In the present device, the rollers are particularly prevented from lateral movement as they pass the inlet 40 and outlet 41 by providing a rib section designated respectively 40b, 41b extending along the entire length of the inlet and outlet angular dimension. The purpose of this particular rib member is more specifically set forth in Patent No. Re. 25,973 concerned with roller pumps which issued Mar. 1, 1966. This particular ribbing section 40b, 41b prevents the rollers 48 from moving laterally as they pass over either the inlet or the outlet openings.

The particular construction of the device permits fluid to be drawn in as the rotor 11 moves past the inlet 40a into each of the individual slots 45 due to the centrifugal force of the roller 48 being driven outwardly, thus providing a vacuum behind and to the area within the slot 45 not occupied by the individual roller members 48. As the rotor 11 continues its rotation carrying along the specific quantity of fluid, the rollers 48 are compressed into and forced into the slot 45, which therefore expels the liquid contained therein. This system is also true of the rotor 11 portions which are not slotted for the individual roller members 48 which contact the interior circumferential surface 13 provide cavities therebetween defined by a pair of rollers 48, the rotor diameter and the Wall 13, and as the rotor 11 rotates, these cavities are increased and decreased in size. The inlet and outlet in a roller pump then may be said to be self-valving in character and no other valving system is required to control the inlet and outlet.

It has been found that the sizing between the respective rollers 48 and their respective containing slots 45 is of particular importance in this device as it does provide a high volume, high pressure pump which may be substantially chatter-proof and rattle-proof due to the basic freedom of the rollers 48 within their respective slots 45 having, at all times, a cushion of fiuid therebetween.

It should be obvious that the present invention has provided new and different concepts for use with roller pumps or the like which includes a predetermined difference in dimension between the diameter of a roller of the pump and the slot within which the roller radially oscillates to shift the available volume for inlet to and outlet from the pump. This dimensional difference is believed to be optimum with a slot having a' width 8 percent greater than the diameter of the roller 48 although the range of dimensional differences may be between 5 and 11 percent. The rollers as described herein are operable in slots which have a depth either equal to or greater than the diameter of the rollers without any marked difference in operation of the unit and stability of the units operation.

What is claimed is:

1. A fluid pump comprising:

(a) a housing having a cylindrical pumping chamber therein;

(b) said pumping chamber being defined by an inner circumferential wall and a pair of spaced circular end walls;

(c) a rotor rotatably mounted within said pumping chamber and having its axis in offset parallel relation to that of said pumping chamber and having a width so as to extend from one of said circular end Walls to the other;

(d) said rotor having a plurality of roller receiving slots formed about the periphery thereof and extending across the entire width thereof, each of said slots comprising a pair of spaced inwardly directed axially and radially parallelly disposed sides providing leading and trailing faces;

(e) a roller disposed for free rotation in each of said slots and having an axial length extending from one of said circular end walls to the other of said circular end walls and having a diameter substantially less than the distance between the faces of said slots, said slot faces being spaced apart a distance from seven to nine percent greater than the diameter of the roller received therein;

(f) the radial depth of said slots being at least equal to the diameter of said rollers;

(g) an inlet port formed through one of said walls, an outlet port formed through one of said walls, said inlet port and said outlet port being arranged in arcuately spaced relationship, and in substantially diametrically opposed position so as to communicate with different of said slots during rotation of said rotor.

2. A fluid pump comprising:

(a) a housing having a cylindrical pumping chamber therein;

(d) said rotor having a plurality of roller receiving slots formed about the periphery thereof and extending across the entire width thereof, each of said slots comprising a pair of spaced inwardly directed axially and radially parallelly disposed sides providing leading and trailing faces;

(e) a roller disposed for free rotation in each of said slots extending from one of said circular end walls to the other of said circular end walls and having a diameter substantially less than the distance between the leading and trailing faces of said slots, said distance between leading and trailing faces being 20 between five percent and eleven percent greater than the roller diameter;

(f) the radial depth of said slots being at least equal to the diameter of said rollers;

(g) a single inlet port communicating with said pumping chamber and being formed through one of said circular end walls; and

(h) a single outlet port communicating with said pumping chamber and being formed through one of said circular end walls, said inlet port and outlet port being diametrically opposed and positioned so as to communicate with said slots during rotation of said rotor.

3. The structure set forth in claim 1 wherein the distance between the slot faces of said rotor are in a range from 7 to 9 percent greater than the diameter of the roller received therein.

4. The structure set forth in claim 1 wherein the distance between the slot faces of said rotor is 8 percent greater than the diameter of the roller received therein.

5. The structure set forth in claim 1 wherein the radial depth of the individual slots is substantially greater than the diameter of the individual rollers received therein so that a substantial clearances forming an effective fluid reservoir will continuously to be maintained inwardly of each roller.

References Cited UNITED STATES PATENTS 1,749,121 3/1930 Barlow 103-136 2,378,390 6/1945 Bertea 103-136 3,253,546 5/1966 Cook l03--136 WILLIAM L. FREEH, Primary Examiner US. Cl. X.R. 91123 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,477,377 November 11, 1969 Harry J. Sadler It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 15, "clearances" should read clearance line 16, "continuously" should read continually Signed and sealed this 21st day of April 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Commissioner of Patents Attesting Officer 

